The present invention relates in general to light coupling, and in particular to diamond and/or silicon carbide coatings applied to light-emitting diodes.
Light-emitting diodes (LEDs) are known in the art and can be made of various materials that radiate light at different wavelengths. For example, ultraviolet light (UV) can be produced by diodes fabricated from silicon carbide using conventional techniques. Where visible light is desired, phosphors that radiate visible light of a desired wavelength in response to the incident UV are placed in contact with the silicon carbide diode. Such diodes and LEDs are used in numerous applications.
Existing silicon carbide diodes convert a large percentage of the UV they generate back into heat because of the high index of refraction of silicon carbide (2.7) as compared to air(1), plastic(1.1) or in-contact phosphors(1.2-0.4). The large index difference results in UV being reflected back into the silicon carbide, heating it This effect limits the efficiency of silicon carbide diodes.
It would therefore be desirable to provide silicon carbide LEDs with higher efficiency.